When choosing a bearing, you must consider several important factors. The first factor to consider is the load that the bearing can support.
There are two types of loads:
– axial load: parallel to the axis of rotation
– radial load: perpendicular to the axis
Each type of bearing is specifically designed to support an axial or radial load. Some bearings can support both loads: in this case we refer to a combined load. If you have to support a combined load, for example, we recommend that you choose a tapered roller bearing. If you need a bearing capable of withstanding a high radial load, then we recommend a cylindrical roller bearing. On the other hand, if your bearing needs to support lighter loads a ball bearing might be sufficient as they are often less expensive.
Rotation speed is another element that should be considered. Some bearings can withstand high speeds. The presence of a cage for cylindrical roller bearings and needle bearings allows for greater speeds than bearings without a cage. However, the choice of a higher speed is sometimes made at the expense of the load. You should also consider the possible presence of misalignment; some bearings are not suitable for this situation, such as double row ball bearings.
You will therefore need to pay attention to the bearing construction: insert and spherical bearings make it easy to support these misalignments. We suggest that you lean towards bearings with automatic alignment which automatically correct alignment defects caused by shaft bending or installation errors. Similarly, operating conditions are very important when choosing the ideal bearing. It is thus necessary to analyze the environment you will be using the bearing in. Your bearing may be subject to a number of contaminations. Some uses can lead to noise disturbance, impact and/or vibration.
Your bearing must therefore withstand this impact on the one hand and not be an inconvenience on the other. Another essential element to consider is the bearing life. Several factors, such as speed or repeated use, can impact the bearing life.
Choosing a sealing system is essential in order to ensure the correct and long-lasting operation of a bearing; it is therefore important to ensure that the bearing is always well-protected from any impurities and external agents, such as dust, water, corrosive fluids or even used lubricants. This choice depends on the type of lubricant, the ambient conditions (and therefore the type of contamination), the fluid pressure and the rotation speed. To give you a good place to start, the fluid pressure is a determining factor in the choice of sealing system. If the pressure is high (in the range of 2-3 bars for example) a mechanical seal is ideal. Otherwise, the choice will be directly linked to the type of lubricant, grease or oil. For example, for grease lubrication the most commonly used solutions are: deflectors or washers, narrow passages that are machined or with grooves; in the case of oil lubrication the sealing system is often accompanied by the presence of a groove for oil recovery.
Conditions of use can also influence your choice, especially when it comes to assembling the bearing. The rigidity and precision that your use requires must also be taken into account. In some cases, you can provide for the application of a preload in the assembly of your bearing to increase its rigidity. Additionally, the preload will have a positive impact on the bearing life and noise level of your system.
Be careful, in order to choose the preload (radial or axial) you must know the rigidity of all parts through software or experimentation. In your selection criteria, you must also consider the ideal material for your bearing. Bearings can be made out of metal, plastic or ceramic. The bearing material depends on its intended use. We recommend that you choose the most compression-resistant bearing. Keep in mind however that the material used affects the price of the bearing.
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Visionary films set in the technologically advanced future have long imagined cars that ride around on frictionless orbs similar to Star Wars’ BB-8. We aren’t there yet, as cars still use wheels and tires to tackle terrain for now, but the modern automobile would not be possible without a different type of roller balls. We’re talking about ball bearings.
Behind virtually every wheel on every newish vehicle, there is a set of tiny ball bearings that keep the wheels smoothly rotating without interruption. They’re unsung heroes when it comes to discussions of a car’s primary parts, but their importance cannot be overstated.
Although these small balls are not a part of the regular maintenance cycle, they do eventually go bad, so it’s important to know how they work when it comes time for repairs. For that reason, The Drive’s reliable informational team has assembled the answers to all your questions in one place. Let’s explore.
Wheel bearings are small metal balls held within small rings that are designed to reduce rolling friction and allow the car’s wheels to spin freely, all while sustaining the vehicle’s weight.
A wheel bearing is located within the wheel hub, which connects the wheel to the axle. Each wheel has its own set of wheel bearings.
The bearing is inside the wheel hub assembly., Depositphotos
Two of the most common types of wheel bearings are ball and roller. One style of wheel bearings used rollers, which were basically a series of small cylinders placed within a tapered circular housing. Roller bearings typically are not sealed, which is good for service but bad for susceptibility to contamination.
Ball bearings, however, use miniature balls with small contact points for rolling ease. Ball bearings are typically sealed, which is great for keeping contamination out, but they often cannot be serviced.
The lifespan of your wheel bearings will depend on the manufacturer, the day-to-day operating conditions, and driving loads, but they are generally expected to last at least 75,000-100,000 miles.
The good thing about a wheel bearing is you’ll know when it goes bad, thanks to a few obvious symptoms. These are the tell-tale signs you need to inspect yours:
The most common symptom of bad wheel bearings is the weird noise they produce when something is off. You might hear humming, whirring, rumbling, grinding, or clicking, depending on how the wheel bearing is failing.
As the ball bearings wear down, they will start to loosen up within their housings and/or lose some of their effectiveness. Because of this, the tires could wear down unevenly.
No, the steering wheel itself won’t feel loose, but the steering feel might. If a bearing goes bad, it might create a bit of play within the wheel assembly. If this occurs, your steering might feel more vague than normal.
If a wheel bearing seal is broken and the insides become contaminated with hard particles, or it has simply worn down over time, it could cause a rougher-than-usual ride and vibrations.
Most modern wheel bearings are sealed and for good reason. If any dirt, debris, or other contamination gets into the bearings, it could reduce lubrication and increase friction. If it gets too hot, or there’s too much debris in the bearings, they could start to lock up or grind. If the bearings lock up, the wheel could lock up.
Pretty much all new wheel hub assemblies come equipped with built-in sensors that inform the traction control, ABS, stability control, and other driver-assistance systems. If something within the wheel bearing isn’t functioning in proper form, it could cause the systems to malfunction, or throw and code and warning light.
Replace the entire wheel hub assembly to replace the wheel bearings., Depositphotos
The best thing to do with a bad wheel bearing is to replace it, along with the others to ensure even and balanced driving. The wheel bearings typically come as part of a larger wheel hub assembly package.
Each car is different and might require different steps, but these are the general steps you will go through when removing a wheel hub assembly.
Note 1: When replacing the hub, you might want to use anti-seize to prevent future difficulties.
Note 2: With everything removed, this is a great time to perform inspections on the suspension and brakes.
Note 3: If you replace one bearing, you should replace the others.
Wheel hub assemblies are often extremely stubborn to remove. If you’re already in the middle of the job but don’t have a puller tool, these other tools and methods might be able to help. Just use extreme caution not to damage anything, and always use necessary safety precautions.
You’ve got questions, The Drive has answers!
A. The only easy checks for bad wheel bearings include a bit of assumption. To start, you want to listen for odd sounds such as humming, whirring, or grinding coming from the suspected wheel. If you hear something and can identify the source to a wheel, you can then jack the car up and check the wheel for movement, slack, or play in its linkage to the car. You can do this by grabbing the wheel by each side and shifting forward and back or side to side.
A. The car might be able to drive, but we do not recommend ever driving with a bad wheel bearing. If you notice symptoms and suspect a bad bearing, immediately drive home or to the repair shop.
A. In one of the worst-case scenarios, the wheel could lock up while driving. That is to say that driving with a bad wheel bearing could be potentially very dangerous.
A. Depending on the car, the average cost of a single wheel hub assembly, not just a bearing, will likely land between $100-300. If you do the job on your own, multiply that by the number of hubs you’re replacing. If you’re taking it to a garage, multiply that number, then add the cost of labor. It won’t be cheap.
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